1. Field of the Invention
The present invention relates, in general, to a field emission cell, which is used as an electron emission source in the state of being printed on a cathode substrate of a display, etc. More specifically, the present invention relates to an emitter composition of a field emission cell, which has a high luminance and a desired emission efficiency even at a low driving voltage by including a carbon nanotube and diamond, a method of manufacturing the same and a field emission cell using the same.
2. Description of the Related Art
In general, a field emission cell, suitable for use in displays, illuminating systems or backlight units, functions to display an image by applying an emitter as an electron emission source with a strong electric field to emit cold electrons, which are then transferred into a vacuum to collide with a fluorescent film to radiate a fluorescent material.
However, the field emission cell is disadvantageous in that gas particles remaining in vacuum collide with the electrons, and thus, are ionized, whereby such gas ions may collide with a micro tip, thus damaging the emission cell. As well, fluorescent particles, which are removed from the fluorescent film, may contaminate the micro tip, and therefore, may shorten a service life of the field emission cell while deteriorating performances thereof.
Thus, there are proposed methods of manufacturing an electron emission source of a field emission cell to be a thick film by using a predetermined amount of carbon nanotube, which are exemplified by a plasma chemical deposition process, a paste process, and an elctrophoresis process.
In particular, according to the paste process, carbon nanotube powders, a binder, glass frit and an organic solvent are mixed to prepare a composition, which is then printed in a uniform thickness on a cathode substrate through a screen printing process, followed by drying in an oven, evenly trimming and then heating by use of a hot burner, thereby obtaining a desired field emission cell.
Accordingly, the above field emission cell has advantages, such as high image quality and uniform emission efficiency. However, when the above field emission cell is applied to a triode type structure having an insulating layer and a gate layer, it has a low current density and a high driving voltage of about 70V, therefore resulting in poor printability, unstable field emission and low emission efficiency.
Although a field emission cell should have a lower driving voltage to economically fabricate end products, such as display panels, the above field emission cell by the paste process is high in a driving voltage due to the use of only the carbon nanotube, and thus, it is practically impossible to fabricate end products at low costs.